CA2097451C - Method for manufacturing master of die for shaping golf ball - Google Patents
Method for manufacturing master of die for shaping golf ballInfo
- Publication number
- CA2097451C CA2097451C CA002097451A CA2097451A CA2097451C CA 2097451 C CA2097451 C CA 2097451C CA 002097451 A CA002097451 A CA 002097451A CA 2097451 A CA2097451 A CA 2097451A CA 2097451 C CA2097451 C CA 2097451C
- Authority
- CA
- Canada
- Prior art keywords
- spherical surface
- dimples
- electrode
- direction perpendicular
- forming step
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23H—WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL
- B23H9/00—Machining specially adapted for treating particular metal objects or for obtaining special effects or results on metal objects
- B23H9/06—Marking or engraving
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23H—WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL
- B23H7/00—Processes or apparatus applicable to both electrical discharge machining and electrochemical machining
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C33/00—Moulds or cores; Details thereof or accessories therefor
- B29C33/42—Moulds or cores; Details thereof or accessories therefor characterised by the shape of the moulding surface, e.g. ribs or grooves
- B29C33/424—Moulding surfaces provided with means for marking or patterning
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
- B29L2031/00—Other particular articles
- B29L2031/54—Balls
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
- B29L2031/00—Other particular articles
- B29L2031/54—Balls
- B29L2031/545—Football balls
Abstract
A method for forming a plurality of small concavities for forming dimples on the surface of the golf ball, on the hemispherical surface of the material of a master by electric discharge machining, is carried out in such a manner that the concavities are nonspherical in the direction perpendicular to the hemispherical surface and in a vertical section through each concavity.
Description
CA 020974~1 1998-01-23 ' ~..,_ METHOD FOR MANUFACTURING A MASTER FOR A DIE
FOR SHAPING GOLF BALLS
The present invention relates to a method for manufacturing a master for making a die for shaping a golf ball.
Normally, the hemispherical concavities of the die are formed by transferring a plurality of small concavities of the master to a material that is to be shaped into the die by various methods. The small concavities for shaping the dimples of the golf ball are formed on the material of the master by a rotary cutting tool. Therefore, these concavities are necessarily circular in the direction perpendicular to the surface of the master.
The golf ball that is formed from a die manufactured by reversing the master thus has only dimples on its surface that are circular a direction perpendicular to the surface of the ball. It is very difficult using the conventional methods to manufacture a golf ball with noncircular dimples.
In recent years, there has developed a growing demand for the formation of dimples that are noncircular, for example, elliptic, polygonal or the like, to improve the aerodynamic characteristics of the ball. But, as described above, it is difficult and takes much time and labor using a conventional method to form noncircular dimple-forming small concavities on the master.
The shape of the dimples of a golf ball is closely related to its flight characteristics. Thus, it is important for the dimensions of the dimples to be held to tolerances as close as approximately 0.001mm and approximately 0.01mm, in the height and bottom width respectively of the convexities on the die that form the dimples.
It is an object of the present invention to provide a method for easily and accurately manufacturing a master for a die for shaping a golf ball by forming a plurality of small concavities for forming dimples on the surface of the ball, on d~
CA 020974~1 1998-01-23 _ -2-a hemispherical surface of material of the master in such a manner that the concavities are noncircular in a direction perpendicular to the hemispherical surface and/or in a vertical section through each concavity.
In accomplishing this and other objects, there is provided a method for forming the plurality of small concavities on the hemispherical surface of the master by electric discharge machining in such a manner that the small concavities are nonspherical in the direction perpendicular to the hemispherical surface and/or in a vertical section through each concavity.
In accordance with one aspect of the invention there is provided a method of manufacturing a master used in forming a female die for creating a golf ball with a plurality of small non-circular shaped dimples on the spherical surface of the golf ball, the steps comprising: detecting the location of an electric discharge means on the spherical surface of a conductive material, said electric discharge means having an electrode with one end corresponding to the size of each of said plurality of non-circular shaped dimples, by using a contact detecting means for detecting when the electrode is in electrical contact with the spherical surface of the conductive material and for outputting detection information to a control means for storing the location of each of said plurality of dimples on the spherical surface of the material and moving the electrode to desired locations using the detection information; and forming each of the plurality of non-circular shaped dimples by electric discharge on the spherical surface of the material using the control means to move the electrode to a position on the spherical surface for each one of said plurality of dimples and in a direction substantially perpendicular to the spherical surface of the material so that each of said dimples is formed in a non-circular shape of in a direction perpendicular to the spherical surface or non-circular in a vertical cross section of the spherical surface or non-circular both in a direction ¢'' CA 020974~1 1998-01-23 ' -2a-perpendicular to the spherical surface and in a vertical cross section of the spherical surface and in a vertical cross section of the spherical surface.
In the drawings:
Fig. 1 is a sectional view showing a golf ball and a die for shaping the golf ball according to a method of an embodiment of the present invention;
Fig. 2 is a sectional view showing a master and part of said die;
Fig. 3 is a perspective view showing apparatus for manufacturing the master and the die;
Fig. 4 is a view showing a portion of the apparatus of Fig. 3;
Fig. 5 is a view showing the vicinity of the lower end of an electrode of the manufacturing apparatus, and a small concavity in the master;
Fig. 6 shows small concavities of various configurations, that can be formed in the material of the master;
Fig. 7 is a view showing another embodiment of the invention; and Fig. 8 is a view showing a further embodiment of the invent lon .
Fig. 1 shows a principal portion of a die 1 for shaping a golf ball 2, the die being made of brass or iron or steel.
Each dimple 3 is nonspherical in the direction perpendicular to the surface of the ball 2 and in a vertical section through the dimple. In the example shown in Fig. 1, each dimple 3 is hexagonal in the direction perpendicular to the ball 2 and triangular in a vertical section through the dimple 3.
CA 020974~1 1998-01-23 ''~, The die 1 comprises a pair of female dies 4 and 4 opposed to each other. Concavities 5 in the reverse configuration of the hemispherical surfaces of the ball 2 are formed in the dies 4.
The concavities 5 are formed by casting, plating or plastic machining using a master 6 shown in Fig. 2 to form a plurality of small convexities 7 on the dies 4 for forming the dimples 3 on the surface of the ball 2.
Referring to Fig. 2, the master 6 comprises a hemispherical body 8 disposed at the lower end of a shaft 9.
A plurality of small concavities 11 is formed on the hemispherical surface 10 of the body 8. These small concavities 11 are used to form convexities 7 that are nonspherical in the direction perpendicular to the surface 10 and in a vertical section through each concavity. In the example shown in Fig. 2, the concavities 11 are hexagonal in the direction perpendicular to the surface 10 and triangular in the vertical section through the concavity.
Fig. 3 shows an apparatus for manufacturing the small concavities 11 in the surface 10. Referring to Figs. 3 and 4, the concavities 11 are formed on a base material 12 of the surface 10 of the master 6 by electric discharge machining using an indexing jig 13 and an electric discharge device 15.
The hardness of the material 12 is in the range from HRC50 to HRC80. More favorably, the hardness of the material 12 is in the range from HRC60 to HRC70. For example, die steel, the hardness of which is in the range from HRC30 to HRC40 is quenched to obtain the above-described hardness.
Use of a material such as a super-hard alloy having a high hardness eliminates the need for quenching in manufacturing the master 6.
The indexing jig 13 comprises a chucking portion 14 for clamping the material 12; a pivotal portion 20 on which the chucking portion 14 is mounted to be rotatable about a V-axis (axis of the chucking portion 14); and a base 21 for CA 020974~1 1998-01-23 ~_ -4-supporting the pivotal portion 20 so that the pivotal portion 20 is rotatable about a horizontal W-axis. The chucking portion 14 and the pivotal portion 20 are driven by means such as a motor.
The electric discharge device 15 comprises an oil reservoir 16 (not shown in detail in the drawings) and a head 17 mounted on a column. The indexing jig 13 is installed on a table portion 18 of the oil reservoir 16. An electrode 22 is held at the lower end of the head 17 by a holding portion 19.
The head 17 is movable in the X, Y and Z directions, all perpendicular to each other. The holding portion 19 is rotatable about a vertical U-axis. The head 17 and the holding portion 19 are driven by means such as a motor.
The means (not shown in the drawings) for driving the chucking portion 14, the pivotal portion 20, the head 17, and the holding portion 19 are sequentially moved to a programmed position or are rotated by a programmed angle according to instructions from a control device so as to accomplish the positioning and indexing thereof.
The electric discharge device 15 has a contact detecting function for detecting the position of the head 17 when the electrode 22 and the material 12 are conductive with each other as a result of contact between the electrode 22 and a workpiece, for example, the material 12 in this embodiment.
The control device stores a plurality of position data detected by the contact detecting function and calculates the position data by four fundamental rules of arithmetic. The results of the calculation are displayed on a screen not shown in the drawings.
Fig. 5 is a view showing the vicinity of the lower end of the electrode 22. In conformity with the configuration of the dimple 3 shown in Fig. 1, the electrode 22 is hexagonal in its transverse cross section, and its lower end is conic or pyramidal. That is, the configuration of the electrode 22 is complementary to that of the dimple 3 in Fig. 1, or similar thereto. The electrode 22 is manufactured by an NC carving device.
~, CA 020974~1 1998-01-23 ............
The pivotal portion 20 of the indexing jig 13 shown in Fig. 3 is rotatable at least 90~ about the W-axis and the chucking portion 14 is rotatable at least 360~ about the V-axis, so that the material 12 is pivotal between a condition in which the material 12 is horizontal and a condition in which the material 12 is vertical.
Referring Figs. 3 and 4, any desired portion of the hemispherical surface 10 of the material 12 can be placed in alignment with the position of the electrode 22 by rotating the pivotal portion 20 and the chucking portion 14.
The small concavities 11 are formed by using the indexing jig 13 and the electric discharge device 15 as follows: The material 12 is held by the chucking portion 14 of the indexing jig 13 with the axis of the material 12 coinciding with the V-axis.
The electrode 22 is held on the holding portion 19 of the device 15 and then the material 12 and the electrode 22 are placed at a machining starting position. At this time, the control device stores data (A) (shown in Fig. 5) of the position at which the contact detecting function has detected contact between the electrode 22 and the surface 10, conduction therebetween, i.e., the control device stores the dimension (A) of the small concavity 11 (shown in Fig. 5) detected, before electric discharge mach;n;ng is performed.
Oil is stored in the oil reservoir 16 before or after the electric discharge machining is effected on the hemispherical surface 10 of the material 12 in a condition set to obtain a predetermined degree of roughness. As a result, a plurality of the small concavities 11 is formed on the surface 10.
Referring to Figs. 2 and 5, the concavities 11 are nonspherical in the direction perpendicular to the surface 10 and in a vertical section through each concavity.
At this time, the pivotal portion 20 and the chucking portion 14 are rotated so that the predetermined positions of the surface 10 of the material 12 to be machined by electric CA 020974~1 1998-01-23 discharge to form the small concavities 11 are sequentially disposed to align with the axis of the electrode 22. As a result, the plurality of concavities 11 is formed on the surface 10.
Preferably, a plurality of the electrodes 22 are used, replacing them sequentially, so that the concavities 11 are formed by a plurality of electric discharge mac-h;ning processes. It is easy to use a plurality of electrodes in different configurations to form the concavities 11. It is also preferable to form the concavities 11 in three processes, namely, a rough machining process, a finishing mac-h;n;ng process, and a super-finishing mach;n;ng process. The conditions of the electric discharge machining of the three processes are differentiated from each other. Each of the rough mach;n;ng, finishing mach;n;ng, and super-finishing machining may itself comprise two or more processes different from each other.
An example of electric discharge machining under the conditions of the contained oil and the non-consumption of electrodes is shown in Table 1 below.
Table 1 Example of electric discharge mach;n;ng Process (7) (8) (9) (10) (ll) (1) 80 80 40 14 6 (2) 40 30 30 16 12 (3) 9 6 4.5 3 1.5 (4) 60 loO 100 120 120 (5) 0.35 0.35 0.35 0.36 0.38 (6) 0.35 0.35 0.35 0.36 0.38 (1) discharge pulse time period: ,u sec (2) suspension pulse time period: ~ sec (3) peak value of main power source: A
.~ .~, CA 020974~1 1998-01-23 '""".,,~
(4) servo reference voltage: V
(5) jump rise time period: sec (6) jump discharge time period: sec (7) first process: rough mach;ning (8) second process: finish mach;n;ng (1) (9) third process: finish machining (2) (10) fourth process: super-finishing machining (1) (11) fifth process: super-finishing machining (2) Referring to Fig. 5, the control device stores data of lo the position (B) at which it has detected contact between the electrode 22 and the surface 10, namely conduction therebetween, i.e., the control device stores the dimension (B) of the small concavity 11 (shown in Fig. 5) detected after the electric discharge machining has been performed. The control device then calculates the difference between data (A) and (B). In this manner, the small concavities 11 can be formed in a desired dimension by the electric discharge machining by correcting the indicated dimension of the small concavity based on the calculated result.
Since the dimension of the small concavities 11 can be measured by the device 15 before and after the electric discharge machining has been performed, it is unnecessary to remove the material 12 from the indexing jig 13 frequently to measure the dimensions of the concavities. Accordingly, the concavities 11 can be formed with a high accuracy and efficiency.
In forming the concavities 11 by electric discharge machining, each of the concavities 11 can be formed on the surface 10 in a desired direction by rotating the electrode 22 at a predetermined angle about the U-axis via the holding portion 19. That is, the golf ball does not have any directionality in its rotation.
~ ,.
CA 020974~1 1998-01-23 As shown in Fig. 6, the small concavities 11 can be formed in various configurations in plan view. For example, elliptical, triangular, pentagonal, cross, star-shaped, rhombic or tear-shaped.
In the embodiment, the small concavities 11 are nonspherical in the direction perpendicular to the surface 10 and in a vertical section through each concavity. It is possible to form the concavities 11 with a circular configuration in vertical section as shown in Fig. 7, by combining any one of the configurations shown in Fig. 6 with that shown in Fig. 7.
It is also possible to form the concavities 11 with a circular configuration in the direction perpendicular to the surface 10 and in a noncircular configuration, such as a triangular configuration, as shown in Fig. 5, or in a trapezoidal configuration in vertical section as shown in Fig. 8.
It is also possible to form on the surface of the golf ball a plurality of dimples with configurations selected from those shown in Fig. 6 in the direction perpendicular to the surface thereof, or to form thereon dimples with two or more noncircular configurations in the vertical section of each concavity. That is, the concavities 11 may be formed in a plurality of noncircular configurations on the surface 10 depending on the requirements.
Since the concavities 11 are formed by electric discharge machining, they can be formed after the material 12 has been heat-treated, unlike the conventional art in which the material of the master of a die is heat-treated after the concavities have been formed by electric discharge mach;n;ng.
That is, the method according to the present invention is capable of forming the concavities 11 on the material 12 more accurately than the conventional method.
~.' CA 020974~1 1998-01-23 _ g _ It is also possible to carve the concavities 11 on the material 12 by rotating or moving the chucking portion 14, the pivotal portion 20, and the oil reservoir 16 simultaneously, while the electric discharge machining is being carried out.
In order to form the small convexities 7 (shown in Figs. 1 and 2), for forming the dimples 3 on the surface of the golf ball, on the inner surface of the concavity 5 of the die 1 without using the master 6, the inner surface of the concavity 5 can be removed, except the portions to be formed into the lo small convexities 7 by electric discharge machining. The small convexities 7 may have a circular configuration or a noncircular configuration in the direction perpendicular to the inner surface of the concavity 5 and/or the vertical section of each convexity 7.
The method for manufacturing the master according to the present invention provides the following effects.
Unlike the conventional method, the noncircular small concavities 11 can be formed on the material 12 of the master 6 of the die 1 with ease and accuracy. The master 6 having the small concavities 11 formed thereon allows the golf ball 2 to have dimples in various noncircular configurations on its surface. Therefore, a golf ball manufactured according to the method of the present invention has a more favorable aerodynamic characteristic than a golf ball manufactured by a conventional method. In addition, the dimples can be freely designed.
It is known that the dimple of a golf ball is closely related to its flight characteristics. The master 6 of the die 1 allows the dimensions of the small convexities 7 of the die 1 to be accurate. As a result, the dimples have a high degree of tolerance and the ball has uniform flight characteristics.
The method according to the present invention allows the master 6 to have a sufficiently high hardness and to be durable.
CA 020974~1 1998-01-23 ~.,~
Although the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications are apparent to those skilled in the art. Such changes and modifications are to be understood as included within the scope of the present invention as defined by the appended claims unless they depart therefrom.
FOR SHAPING GOLF BALLS
The present invention relates to a method for manufacturing a master for making a die for shaping a golf ball.
Normally, the hemispherical concavities of the die are formed by transferring a plurality of small concavities of the master to a material that is to be shaped into the die by various methods. The small concavities for shaping the dimples of the golf ball are formed on the material of the master by a rotary cutting tool. Therefore, these concavities are necessarily circular in the direction perpendicular to the surface of the master.
The golf ball that is formed from a die manufactured by reversing the master thus has only dimples on its surface that are circular a direction perpendicular to the surface of the ball. It is very difficult using the conventional methods to manufacture a golf ball with noncircular dimples.
In recent years, there has developed a growing demand for the formation of dimples that are noncircular, for example, elliptic, polygonal or the like, to improve the aerodynamic characteristics of the ball. But, as described above, it is difficult and takes much time and labor using a conventional method to form noncircular dimple-forming small concavities on the master.
The shape of the dimples of a golf ball is closely related to its flight characteristics. Thus, it is important for the dimensions of the dimples to be held to tolerances as close as approximately 0.001mm and approximately 0.01mm, in the height and bottom width respectively of the convexities on the die that form the dimples.
It is an object of the present invention to provide a method for easily and accurately manufacturing a master for a die for shaping a golf ball by forming a plurality of small concavities for forming dimples on the surface of the ball, on d~
CA 020974~1 1998-01-23 _ -2-a hemispherical surface of material of the master in such a manner that the concavities are noncircular in a direction perpendicular to the hemispherical surface and/or in a vertical section through each concavity.
In accomplishing this and other objects, there is provided a method for forming the plurality of small concavities on the hemispherical surface of the master by electric discharge machining in such a manner that the small concavities are nonspherical in the direction perpendicular to the hemispherical surface and/or in a vertical section through each concavity.
In accordance with one aspect of the invention there is provided a method of manufacturing a master used in forming a female die for creating a golf ball with a plurality of small non-circular shaped dimples on the spherical surface of the golf ball, the steps comprising: detecting the location of an electric discharge means on the spherical surface of a conductive material, said electric discharge means having an electrode with one end corresponding to the size of each of said plurality of non-circular shaped dimples, by using a contact detecting means for detecting when the electrode is in electrical contact with the spherical surface of the conductive material and for outputting detection information to a control means for storing the location of each of said plurality of dimples on the spherical surface of the material and moving the electrode to desired locations using the detection information; and forming each of the plurality of non-circular shaped dimples by electric discharge on the spherical surface of the material using the control means to move the electrode to a position on the spherical surface for each one of said plurality of dimples and in a direction substantially perpendicular to the spherical surface of the material so that each of said dimples is formed in a non-circular shape of in a direction perpendicular to the spherical surface or non-circular in a vertical cross section of the spherical surface or non-circular both in a direction ¢'' CA 020974~1 1998-01-23 ' -2a-perpendicular to the spherical surface and in a vertical cross section of the spherical surface and in a vertical cross section of the spherical surface.
In the drawings:
Fig. 1 is a sectional view showing a golf ball and a die for shaping the golf ball according to a method of an embodiment of the present invention;
Fig. 2 is a sectional view showing a master and part of said die;
Fig. 3 is a perspective view showing apparatus for manufacturing the master and the die;
Fig. 4 is a view showing a portion of the apparatus of Fig. 3;
Fig. 5 is a view showing the vicinity of the lower end of an electrode of the manufacturing apparatus, and a small concavity in the master;
Fig. 6 shows small concavities of various configurations, that can be formed in the material of the master;
Fig. 7 is a view showing another embodiment of the invention; and Fig. 8 is a view showing a further embodiment of the invent lon .
Fig. 1 shows a principal portion of a die 1 for shaping a golf ball 2, the die being made of brass or iron or steel.
Each dimple 3 is nonspherical in the direction perpendicular to the surface of the ball 2 and in a vertical section through the dimple. In the example shown in Fig. 1, each dimple 3 is hexagonal in the direction perpendicular to the ball 2 and triangular in a vertical section through the dimple 3.
CA 020974~1 1998-01-23 ''~, The die 1 comprises a pair of female dies 4 and 4 opposed to each other. Concavities 5 in the reverse configuration of the hemispherical surfaces of the ball 2 are formed in the dies 4.
The concavities 5 are formed by casting, plating or plastic machining using a master 6 shown in Fig. 2 to form a plurality of small convexities 7 on the dies 4 for forming the dimples 3 on the surface of the ball 2.
Referring to Fig. 2, the master 6 comprises a hemispherical body 8 disposed at the lower end of a shaft 9.
A plurality of small concavities 11 is formed on the hemispherical surface 10 of the body 8. These small concavities 11 are used to form convexities 7 that are nonspherical in the direction perpendicular to the surface 10 and in a vertical section through each concavity. In the example shown in Fig. 2, the concavities 11 are hexagonal in the direction perpendicular to the surface 10 and triangular in the vertical section through the concavity.
Fig. 3 shows an apparatus for manufacturing the small concavities 11 in the surface 10. Referring to Figs. 3 and 4, the concavities 11 are formed on a base material 12 of the surface 10 of the master 6 by electric discharge machining using an indexing jig 13 and an electric discharge device 15.
The hardness of the material 12 is in the range from HRC50 to HRC80. More favorably, the hardness of the material 12 is in the range from HRC60 to HRC70. For example, die steel, the hardness of which is in the range from HRC30 to HRC40 is quenched to obtain the above-described hardness.
Use of a material such as a super-hard alloy having a high hardness eliminates the need for quenching in manufacturing the master 6.
The indexing jig 13 comprises a chucking portion 14 for clamping the material 12; a pivotal portion 20 on which the chucking portion 14 is mounted to be rotatable about a V-axis (axis of the chucking portion 14); and a base 21 for CA 020974~1 1998-01-23 ~_ -4-supporting the pivotal portion 20 so that the pivotal portion 20 is rotatable about a horizontal W-axis. The chucking portion 14 and the pivotal portion 20 are driven by means such as a motor.
The electric discharge device 15 comprises an oil reservoir 16 (not shown in detail in the drawings) and a head 17 mounted on a column. The indexing jig 13 is installed on a table portion 18 of the oil reservoir 16. An electrode 22 is held at the lower end of the head 17 by a holding portion 19.
The head 17 is movable in the X, Y and Z directions, all perpendicular to each other. The holding portion 19 is rotatable about a vertical U-axis. The head 17 and the holding portion 19 are driven by means such as a motor.
The means (not shown in the drawings) for driving the chucking portion 14, the pivotal portion 20, the head 17, and the holding portion 19 are sequentially moved to a programmed position or are rotated by a programmed angle according to instructions from a control device so as to accomplish the positioning and indexing thereof.
The electric discharge device 15 has a contact detecting function for detecting the position of the head 17 when the electrode 22 and the material 12 are conductive with each other as a result of contact between the electrode 22 and a workpiece, for example, the material 12 in this embodiment.
The control device stores a plurality of position data detected by the contact detecting function and calculates the position data by four fundamental rules of arithmetic. The results of the calculation are displayed on a screen not shown in the drawings.
Fig. 5 is a view showing the vicinity of the lower end of the electrode 22. In conformity with the configuration of the dimple 3 shown in Fig. 1, the electrode 22 is hexagonal in its transverse cross section, and its lower end is conic or pyramidal. That is, the configuration of the electrode 22 is complementary to that of the dimple 3 in Fig. 1, or similar thereto. The electrode 22 is manufactured by an NC carving device.
~, CA 020974~1 1998-01-23 ............
The pivotal portion 20 of the indexing jig 13 shown in Fig. 3 is rotatable at least 90~ about the W-axis and the chucking portion 14 is rotatable at least 360~ about the V-axis, so that the material 12 is pivotal between a condition in which the material 12 is horizontal and a condition in which the material 12 is vertical.
Referring Figs. 3 and 4, any desired portion of the hemispherical surface 10 of the material 12 can be placed in alignment with the position of the electrode 22 by rotating the pivotal portion 20 and the chucking portion 14.
The small concavities 11 are formed by using the indexing jig 13 and the electric discharge device 15 as follows: The material 12 is held by the chucking portion 14 of the indexing jig 13 with the axis of the material 12 coinciding with the V-axis.
The electrode 22 is held on the holding portion 19 of the device 15 and then the material 12 and the electrode 22 are placed at a machining starting position. At this time, the control device stores data (A) (shown in Fig. 5) of the position at which the contact detecting function has detected contact between the electrode 22 and the surface 10, conduction therebetween, i.e., the control device stores the dimension (A) of the small concavity 11 (shown in Fig. 5) detected, before electric discharge mach;n;ng is performed.
Oil is stored in the oil reservoir 16 before or after the electric discharge machining is effected on the hemispherical surface 10 of the material 12 in a condition set to obtain a predetermined degree of roughness. As a result, a plurality of the small concavities 11 is formed on the surface 10.
Referring to Figs. 2 and 5, the concavities 11 are nonspherical in the direction perpendicular to the surface 10 and in a vertical section through each concavity.
At this time, the pivotal portion 20 and the chucking portion 14 are rotated so that the predetermined positions of the surface 10 of the material 12 to be machined by electric CA 020974~1 1998-01-23 discharge to form the small concavities 11 are sequentially disposed to align with the axis of the electrode 22. As a result, the plurality of concavities 11 is formed on the surface 10.
Preferably, a plurality of the electrodes 22 are used, replacing them sequentially, so that the concavities 11 are formed by a plurality of electric discharge mac-h;ning processes. It is easy to use a plurality of electrodes in different configurations to form the concavities 11. It is also preferable to form the concavities 11 in three processes, namely, a rough machining process, a finishing mac-h;n;ng process, and a super-finishing mach;n;ng process. The conditions of the electric discharge machining of the three processes are differentiated from each other. Each of the rough mach;n;ng, finishing mach;n;ng, and super-finishing machining may itself comprise two or more processes different from each other.
An example of electric discharge machining under the conditions of the contained oil and the non-consumption of electrodes is shown in Table 1 below.
Table 1 Example of electric discharge mach;n;ng Process (7) (8) (9) (10) (ll) (1) 80 80 40 14 6 (2) 40 30 30 16 12 (3) 9 6 4.5 3 1.5 (4) 60 loO 100 120 120 (5) 0.35 0.35 0.35 0.36 0.38 (6) 0.35 0.35 0.35 0.36 0.38 (1) discharge pulse time period: ,u sec (2) suspension pulse time period: ~ sec (3) peak value of main power source: A
.~ .~, CA 020974~1 1998-01-23 '""".,,~
(4) servo reference voltage: V
(5) jump rise time period: sec (6) jump discharge time period: sec (7) first process: rough mach;ning (8) second process: finish mach;n;ng (1) (9) third process: finish machining (2) (10) fourth process: super-finishing machining (1) (11) fifth process: super-finishing machining (2) Referring to Fig. 5, the control device stores data of lo the position (B) at which it has detected contact between the electrode 22 and the surface 10, namely conduction therebetween, i.e., the control device stores the dimension (B) of the small concavity 11 (shown in Fig. 5) detected after the electric discharge machining has been performed. The control device then calculates the difference between data (A) and (B). In this manner, the small concavities 11 can be formed in a desired dimension by the electric discharge machining by correcting the indicated dimension of the small concavity based on the calculated result.
Since the dimension of the small concavities 11 can be measured by the device 15 before and after the electric discharge machining has been performed, it is unnecessary to remove the material 12 from the indexing jig 13 frequently to measure the dimensions of the concavities. Accordingly, the concavities 11 can be formed with a high accuracy and efficiency.
In forming the concavities 11 by electric discharge machining, each of the concavities 11 can be formed on the surface 10 in a desired direction by rotating the electrode 22 at a predetermined angle about the U-axis via the holding portion 19. That is, the golf ball does not have any directionality in its rotation.
~ ,.
CA 020974~1 1998-01-23 As shown in Fig. 6, the small concavities 11 can be formed in various configurations in plan view. For example, elliptical, triangular, pentagonal, cross, star-shaped, rhombic or tear-shaped.
In the embodiment, the small concavities 11 are nonspherical in the direction perpendicular to the surface 10 and in a vertical section through each concavity. It is possible to form the concavities 11 with a circular configuration in vertical section as shown in Fig. 7, by combining any one of the configurations shown in Fig. 6 with that shown in Fig. 7.
It is also possible to form the concavities 11 with a circular configuration in the direction perpendicular to the surface 10 and in a noncircular configuration, such as a triangular configuration, as shown in Fig. 5, or in a trapezoidal configuration in vertical section as shown in Fig. 8.
It is also possible to form on the surface of the golf ball a plurality of dimples with configurations selected from those shown in Fig. 6 in the direction perpendicular to the surface thereof, or to form thereon dimples with two or more noncircular configurations in the vertical section of each concavity. That is, the concavities 11 may be formed in a plurality of noncircular configurations on the surface 10 depending on the requirements.
Since the concavities 11 are formed by electric discharge machining, they can be formed after the material 12 has been heat-treated, unlike the conventional art in which the material of the master of a die is heat-treated after the concavities have been formed by electric discharge mach;n;ng.
That is, the method according to the present invention is capable of forming the concavities 11 on the material 12 more accurately than the conventional method.
~.' CA 020974~1 1998-01-23 _ g _ It is also possible to carve the concavities 11 on the material 12 by rotating or moving the chucking portion 14, the pivotal portion 20, and the oil reservoir 16 simultaneously, while the electric discharge machining is being carried out.
In order to form the small convexities 7 (shown in Figs. 1 and 2), for forming the dimples 3 on the surface of the golf ball, on the inner surface of the concavity 5 of the die 1 without using the master 6, the inner surface of the concavity 5 can be removed, except the portions to be formed into the lo small convexities 7 by electric discharge machining. The small convexities 7 may have a circular configuration or a noncircular configuration in the direction perpendicular to the inner surface of the concavity 5 and/or the vertical section of each convexity 7.
The method for manufacturing the master according to the present invention provides the following effects.
Unlike the conventional method, the noncircular small concavities 11 can be formed on the material 12 of the master 6 of the die 1 with ease and accuracy. The master 6 having the small concavities 11 formed thereon allows the golf ball 2 to have dimples in various noncircular configurations on its surface. Therefore, a golf ball manufactured according to the method of the present invention has a more favorable aerodynamic characteristic than a golf ball manufactured by a conventional method. In addition, the dimples can be freely designed.
It is known that the dimple of a golf ball is closely related to its flight characteristics. The master 6 of the die 1 allows the dimensions of the small convexities 7 of the die 1 to be accurate. As a result, the dimples have a high degree of tolerance and the ball has uniform flight characteristics.
The method according to the present invention allows the master 6 to have a sufficiently high hardness and to be durable.
CA 020974~1 1998-01-23 ~.,~
Although the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications are apparent to those skilled in the art. Such changes and modifications are to be understood as included within the scope of the present invention as defined by the appended claims unless they depart therefrom.
Claims (16)
1. A method of manufacturing a master used in forming a female die for creating a golf ball with a plurality of small non-circular shaped dimples on the spherical surface of the golf ball, the steps comprising:
detecting the location of an electric discharge means on the spherical surface of a conductive material, said electric discharge means having an electrode with one end corresponding to the size of each of said plurality of non-circular shaped dimples, by using a contact detecting means for detecting when the electrode is in electrical contact with the spherical surface of the conductive material and for outputting detection information to a control means for storing the location of each of said plurality of dimples on the spherical surface of the material and moving the electrode to desired locations using the detection information; and forming each of the plurality of non-circular shaped dimples by electric discharge on the spherical surface of the material using the control means to move the electrode to a position on the spherical surface for each one of said plurality of dimples and in a direction substantially perpendicular to the spherical surface of the material so that each of said dimples is formed in a non-circular shape of in a direction perpendicular to the spherical surface or non-circular in a vertical cross section of the spherical surface or non-circular both in a direction perpendicular to the spherical surface and in a vertical cross section of the spherical surface.
detecting the location of an electric discharge means on the spherical surface of a conductive material, said electric discharge means having an electrode with one end corresponding to the size of each of said plurality of non-circular shaped dimples, by using a contact detecting means for detecting when the electrode is in electrical contact with the spherical surface of the conductive material and for outputting detection information to a control means for storing the location of each of said plurality of dimples on the spherical surface of the material and moving the electrode to desired locations using the detection information; and forming each of the plurality of non-circular shaped dimples by electric discharge on the spherical surface of the material using the control means to move the electrode to a position on the spherical surface for each one of said plurality of dimples and in a direction substantially perpendicular to the spherical surface of the material so that each of said dimples is formed in a non-circular shape of in a direction perpendicular to the spherical surface or non-circular in a vertical cross section of the spherical surface or non-circular both in a direction perpendicular to the spherical surface and in a vertical cross section of the spherical surface.
2. The method as defined in claim 1, wherein prior to the process of forming, the material is of a hardness in the range of between 50 to 80 degrees in HRC.
3. The method as defined in claim 1, wherein said detecting step further comprising determining a starting position for the electrode with respect to the spherical surface of the conductive material prior to forming the plurality of dimples wherein the starting position is determined by electrical contact between the electrode and the material.
4. The method as defined in claim 1, wherein the step of forming further comprising the steps of:
rough working the spherical surface of the material prior to forming the plurality of dimples;
finish working the spherical surface of the material after the dimples are formed; and super finish working the spherical surface after the finish working step.
rough working the spherical surface of the material prior to forming the plurality of dimples;
finish working the spherical surface of the material after the dimples are formed; and super finish working the spherical surface after the finish working step.
5. The method as defined in claim 4, wherein in said forming step, a different electrode is used in each of said steps of rough working, finish working and super finish working.
6. The method as defined in claim 1, wherein in said forming step each of said plurality of dimples is in the shape of a pyramid.
7. The method as defined in claim 1, wherein in said forming step each of said plurality of non-circular shaped dimples is formed in the shape of a truncated pyramid.
8. The method as defined in claim 1, wherein in said forming step each of said plurality of non-circular shaped dimples is elliptically shaped in a direction perpendicular to the spherical surface of the material.
9. The method as defined in claim 1, wherein in said forming step each of said plurality of non-circular shaped dimples is triangular shaped in a direction perpendicular to the spherical surface of the material.
10. The method as defined in claim 1, wherein in said forming step each of said plurality of non-circular shaped dimples is pentagon shaped in a direction perpendicular to the spherical surface of the material.
11. The method as defined in claim 1, wherein in said forming step each of said plurality of non-circular shaped dimples is star shaped in a direction perpendicular to the spherical surface of the material.
12. The method as defined in claim 1, wherein in said forming step each of said plurality of non-circular shaped dimples is star shaped in a direction perpendicular to the spherical surface of the material.
13. The method as defined in claim 1, wherein in said forming step each of said plurality of non-circular shaped dimples is tear shaped in a direction perpendicular to the spherical surface of the material.
14. The method as defined in claim 1, wherein in said forming step each of said plurality of non-circular shaped dimples is cross shaped in a direction perpendicular to the spherical surface of the material.
15. The method as defined in claim 1, further comprising:
before said detecting step, holding said conductive material in an indexing jig having a chuck supported by a rotatable portion; and wherein in said forming step, moving the conductive material with respect to said electrode by rotating said chuck in a first direction and said rotatable portion in a second direction.
before said detecting step, holding said conductive material in an indexing jig having a chuck supported by a rotatable portion; and wherein in said forming step, moving the conductive material with respect to said electrode by rotating said chuck in a first direction and said rotatable portion in a second direction.
16. The method as defined in claim 1, wherein in said forming step each of said non-circular dimples being formed by repeating electrical discharges while moving the electrode between a first position near the spherical surface of the material to a second position comparatively further from the surface until each respective dimple is formed.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4-174692 | 1992-06-08 | ||
| JP17469292 | 1992-06-08 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2097451A1 CA2097451A1 (en) | 1993-12-09 |
| CA2097451C true CA2097451C (en) | 1999-01-26 |
Family
ID=15983014
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002097451A Expired - Fee Related CA2097451C (en) | 1992-06-08 | 1993-06-01 | Method for manufacturing master of die for shaping golf ball |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US5406043A (en) |
| EP (2) | EP0839622B1 (en) |
| KR (1) | KR100268688B1 (en) |
| AU (1) | AU666010B2 (en) |
| CA (1) | CA2097451C (en) |
| DE (2) | DE69333291T2 (en) |
| TW (1) | TW221383B (en) |
Families Citing this family (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5720676A (en) * | 1995-07-25 | 1998-02-24 | Bridgestone Sports Co., Ltd. | Golf ball |
| AU5289498A (en) * | 1997-02-05 | 1998-08-13 | Johnson & Johnson Research Pty. Limited | Basecurve mold designs to maintain HEMA ring/basecurve adhesion |
| US5890975A (en) * | 1997-06-05 | 1999-04-06 | Lisco, Inc. | Golf ball and method of forming dimples thereon |
| US6206792B1 (en) * | 1997-06-05 | 2001-03-27 | Spalding Sports Worldwide, Inc. | Golf ball having elongated dimples and method for making the same |
| JP4796226B2 (en) | 1999-11-18 | 2011-10-19 | キャラウェイ・ゴルフ・カンパニ | Golf ball mold |
| US6390740B1 (en) | 2000-10-03 | 2002-05-21 | Spalding Sports Worldwide, Inc. | Non-circular dimples formed via an orbital pantograph cutter |
| US6422850B1 (en) * | 2000-10-19 | 2002-07-23 | Spalding Sports Worldwide, Inc. | Non-circular vent pin for golf ball injection mold |
| US20020169031A1 (en) * | 2001-01-31 | 2002-11-14 | Wallace Justin Q. | Golf club grip mold apparatus and method |
| KR100673964B1 (en) * | 2005-01-28 | 2007-01-24 | 삼성테크윈 주식회사 | Eletric discharge machining for turbine blade and eletric discharge machine adapted for the same |
| KR101091962B1 (en) | 2009-04-13 | 2011-12-09 | 김윤태 | A mold for molding a medal frosted on its raised character part and method for manufacturing thereof |
| CN102151920B (en) * | 2011-03-02 | 2012-06-27 | 哈尔滨工业大学 | Electrical discharge machining (EDM) method of super-hard micro-hemisphere couple part |
| US8991287B2 (en) * | 2012-07-06 | 2015-03-31 | Caterpillar Inc. | Surface dimpling on rotating work piece using rotation cutting tool |
| WO2017002326A1 (en) * | 2015-06-29 | 2017-01-05 | 兼房株式会社 | Dimpling method using end mill and end mill |
| CN106584725B (en) * | 2016-11-24 | 2019-01-29 | 嘉善傲博体育用品有限公司 | A kind of interior ball surface roughening equipment for basketball wrapping |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3498158A (en) * | 1968-06-07 | 1970-03-03 | Gti Corp | Steel embossing die and methods of making the same |
| US4409457A (en) * | 1979-03-08 | 1983-10-11 | Bridgeport Tire Co. Ltd. | System for manufacturing tire molding metal molds with electrical discharge machining |
| SU860979A1 (en) * | 1979-12-26 | 1981-09-07 | Научно-Исследовательский Отдел 8320 Предприятия П/Я Р-6115 | Electrochemical treatment method |
| JPS5828425A (en) * | 1981-08-12 | 1983-02-19 | Inst Tech Precision Eng | Electrospark machining apparatus |
| JPS6048223A (en) * | 1983-08-26 | 1985-03-15 | Inoue Japax Res Inc | Marking device |
| CH661890A5 (en) * | 1983-10-01 | 1987-08-31 | Werner Ullmann | DRIVE FOR A MACHINE FOR THE PRODUCTION OF A WORKPIECE OF A SPECIFIC ROOM MOLD BY MEANS OF A MOLD GRINDING TOOL. |
| FR2601271B1 (en) * | 1986-07-10 | 1990-07-13 | Banque De France | PROCESS FOR MANUFACTURING A TOOL FOR THE STAMPING OF ROUND CANVAS OF A ROUND FORM USED FOR MAKING WATERCOLORS, AND APPARATUS FOR IMPLEMENTING THE PROCESS. |
| JP2551048B2 (en) * | 1986-11-19 | 1996-11-06 | ブリヂストンスポーツ株式会社 | Golf ball |
| GB8803106D0 (en) * | 1988-02-11 | 1988-03-09 | Dunlop Ltd | Golf ball dimple pattern |
| JPH02295573A (en) * | 1989-05-09 | 1990-12-06 | Sumitomo Rubber Ind Ltd | Short range golf ball |
| US4954022A (en) * | 1989-06-16 | 1990-09-04 | Underwood Mold Co., Inc. | Method for machining multiple cuts in a workpiece to a uniform depth |
| GB2242363B (en) * | 1990-03-27 | 1994-07-13 | Dunlop Ltd | Golf balls with isodiametrical dimples |
| JP2896590B2 (en) * | 1990-04-25 | 1999-05-31 | ブリヂストンスポーツ株式会社 | Manufacturing method of prototype master for golf ball |
| JPH0463663A (en) * | 1990-06-29 | 1992-02-28 | Mitsubishi Electric Corp | Positioning device for discharge machining electrode |
| JP2844874B2 (en) * | 1990-07-27 | 1999-01-13 | 住友ゴム工業株式会社 | Golf ball |
-
1993
- 1993-05-31 TW TW082104299A patent/TW221383B/zh active
- 1993-06-01 CA CA002097451A patent/CA2097451C/en not_active Expired - Fee Related
- 1993-06-01 AU AU39923/93A patent/AU666010B2/en not_active Ceased
- 1993-06-03 DE DE69333291T patent/DE69333291T2/en not_active Expired - Fee Related
- 1993-06-03 DE DE69321035T patent/DE69321035T2/en not_active Expired - Fee Related
- 1993-06-03 EP EP98102115A patent/EP0839622B1/en not_active Expired - Lifetime
- 1993-06-03 EP EP93108956A patent/EP0573900B1/en not_active Expired - Lifetime
- 1993-06-07 KR KR1019930010206A patent/KR100268688B1/en not_active IP Right Cessation
- 1993-06-08 US US08/073,041 patent/US5406043A/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| EP0573900A1 (en) | 1993-12-15 |
| AU3992393A (en) | 1993-12-09 |
| KR940005344A (en) | 1994-03-21 |
| DE69333291T2 (en) | 2004-09-09 |
| EP0839622B1 (en) | 2003-11-05 |
| EP0839622A3 (en) | 2001-02-28 |
| EP0839622A2 (en) | 1998-05-06 |
| TW221383B (en) | 1994-03-01 |
| DE69321035T2 (en) | 1999-05-12 |
| US5406043A (en) | 1995-04-11 |
| EP0573900B1 (en) | 1998-09-16 |
| KR100268688B1 (en) | 2000-10-16 |
| AU666010B2 (en) | 1996-01-25 |
| DE69321035D1 (en) | 1998-10-22 |
| CA2097451A1 (en) | 1993-12-09 |
| DE69333291D1 (en) | 2003-12-11 |
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